Inter-planner variation in treatment-plan quality of plans created with a knowledge-based treatment planning system

• Published in: Physica medica Vol. 67; pp. 132 - 140
• Main Authors: Kubo, Kazuki, Monzen, Hajime, Ishii, Kentaro, Tamura, Mikoto, Nakasaka, Yuta, Kusawake, Masayuki, Kishimoto, Shun, Nakahara, Ryuta, Matsuda, Shogo, Nakajima, Toshifumi, Kawamorita, Ryu
• Format: Journal Article
• Language: English
• Published: Italy Elsevier Ltd 01.11.2019
• Subjects: Dose Fractionation, Radiation; Humans; Inter-planner variation; Knowledge-based treatment planning system; Male; Prostate; Prostatic Neoplasms - radiotherapy; Quality Control; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Intensity-Modulated; VMAT; VMAT; Inter-planner variation; Prostate; Knowledge-based treatment planning system
• ISSN: 1120-1797; 1724-191X
• DOI: 10.1016/j.ejmp.2019.10.032

•Clarify the inter-planner variation of knowledge-based plan (KBP) quality.•Ninety VMAT plans were created using the RapidPlan by nine planners.•Single optimization with only priority modification was performed.•Large variation of plan quality was observed in beginner planners.•Inter-planner variation remains for complicated plans even though using KBP. This study aimed to clarify the inter-planner variation of plan quality in knowledge-based plans created by nine planners. Five hypofractionated prostate-only (HPO) volumetric modulated arc therapy (VMAT) plans and five whole-pelvis (WP) VMAT plans were created by each planner using a knowledge-based planning (KBP) system. Nine planners were divided into three groups of three planners each: Senior, Junior, and Beginner. Single optimization with only priority modification for all objectives was performed to stay within the dose constraints. The coefficients of variation (CVs) for dosimetric parameters were evaluated, and a plan quality metric (PQM) was used to evaluate comprehensive plan quality. Lower CVs (<0.05) were observed at dosimetric parameters in the planning target volume for both HPO and WP plans, while the CVs in the rectum and bladder for WP plans (<0.91) were greater than those for HPO plans (<0.17). The PQM values of HPO plans for Cases1–5 (average ± standard deviation) were 41.2 ± 7.1, 40.9 ± 5.6, and 39.9 ± 4.6 in the Senior, Junior, and Beginner groups, respectively. For the WP plans, the PQM values were 51.9 ± 6.3, 47.5 ± 4.3, and 40.0 ± 6.6, respectively. The number of clinically acceptable HPO and WP plans were 13/15 and 11/15 in the Senior group, 13/15 and 10/15 plans in the Junior group, and 8/15 and 2/15 plans in the Beginner group, respectively. Inter-planner variation in the plan quality with RapidPlan remains, especially for the complicated VMAT plans, due to planners’ heuristics.